Welding apparatus



Jan. 25, 1944 MORRIS 2,339,795

WELDING APPARATUS Filed Jan. 21, 1941 Ho WA RD 1 MORRIS ATTORNEY Patented Jan. 25 1944 2,339,795 WELDING APPARATUS Howard I. Morris, Lakewood, Ohio, assignor of one-third to Carl M. Yoder and one-third to Harvey 0. Yoder, both of Lakewood, Ohio Application January 21, 1941, Serial No. 375,157

7 Claims. (Cl. 219-6) This invention relates to apparatus for and process of welding materials and preformed stock,

for example, the seams of tubing.

.One object of the invention is .to provide an improved apparatus of this character-oi unitary construction wherein alternating current supplied from a suitable source is by mechanical means rectified into direct current and the latter connected to the welding electrodes for welding materials.

Another object of the invention is to provide an improved apparatus and'process wherein rectitled alternating current is employed for welding materials, whereby the molecular structure constituting the welded seam has a uniform texture and density throughout the length thereof.

Another object of the invention is to provide a welding apparatus supplied initially with alternating current from a. power circuit and provided with means for supplying the current to the welding electrodes without afiecting the balanced condition in the power circuit.

"This form of construction and process have many advantages. In practically all localities only alternating current is avaiiable for commercial as well as domestic use. It therefore enables the user to not only eflect welding operations with direct current, but to readily employ direct current at low voltage since the alternating current maybe stepped down by means of a transformer before it is rectified. It also eliminates the installation of a direct current generator and power means for operating it. Since a direct current generator for generating a low voltage suitable for welding purposes occupies considerable space and is an expensive apparatus, my apparatus insures a large saving and is relatively small as well as of simplified construction.

Also, in practically all welding apparatus employing alternating current, only one phase of the current is used for Welding and as it is customary for the power supply circuits to be of the three phase character, the use of one phase results in an unbalanced condition in the circuit. In my apparatus, the welding operations eifect a pull equally onall three phases of the power circuit and thus keeps the .latter evenly balanced.

Other objects of the invention will be apparent to those skilled in the art to which my invention relates from the following description taken in connection with the accomanying drawing,

wherein Fig. 1 illustrates diagrammatically an ap aratus embodying my invention:

Figs. 2 to 6 are views similar to Fig. 1 but showing therewith the position of the parts throughout a portion of one complete cycl of a three phase alternating current supply and Fig. 'I is an enlarged elevation of the work holding, advancing and welding elements.

In the drawing, l, 2, 3-, indicate the supply mains, of a three phase alternating current circuit connected by leads la, lb, lc, respectively, to a synchronous motor 4, which is connected to and'drives a shaft 5. The shaft 5 is mounted in hearings in suitable housings or standards (not shown) the motor 4 and housings or standards being secured in position on a support (not shown). The leads I, 2, 3, are also connected to leads la, lb, l'c, which are connected to the primary windings 6' of a transformer '1', having secondary windings 8' arranged'to step the voltage impressed on the leads I, 2, 3, down to the desired voltage for welding. The secondary windings 8 are connected by leads la, lb", lc" to leads l6, l6, l6", respectively, which in turn are connected to brushes l5, l5, l5", respectively. The brushes l5, l5, l5" engage rings l4, l4, l4, respectively, each mounted on and insulated from a disk fixed to'the shaft 5. By means of series of contacts between each ring and direct current mains 6, 'l, the leads la", lb", lc", are connected to the latter mains 6, l', in co-ordinated relation to the reversal of current flow therein, so that the current in the direct I .current mains is uni-directional at all times. The

ter in turn engage a tube A, which may be fed to the electrodes by its shaping mechanism (not shown) or other feeding means, for example, rolls 9a. The rolls 9a. may be driven through suitable gearing 9b, the supports for the rolls being adjustable toward and from each other to insure engagement with the tube under the desired pressure and to accommodate the rolls to tubing having different external diameters. The feeding of the tube may serve as the means for rotating the electrodes. The tube shaping mechanism or tube feeding means and the mounting for the electrodes may be of any desired form of construction for which reason such mechanism, feeding means and mounting are not shown;

-I provide series of contacts for each alternating current supply-main la", lb", lc". The series of contacts for lead la" consists of (a) a set of contacts or segments Ill, which are suitably mounted indiametrical relation on a disk ll fixed to the shaft 5 and insulated from each other and the disk, electrically connected to the ring II, which is engaged by the brush I! connected by lead I6 t the leadla", the ring I4 being fixed to and insulated from the disk Ila which is rotated by the shaft (b) a set of contacts comprising brushes I2 connected by leads I2a to the direct current main 8; and (c) a set of contacts comprising brushes it connected by leads Ila to.the direct current min I, the brushes of each set being diametrically related so as to be engaged by and disengaged from the elements I I simultaneously and each brush l2' being disposed angularly 90 from the brushes II. In the disclosure herein, for reasons which will be apparent, the length of the insulation between the segments I I is twice the length of the latter.

The series of contacts for the lead lb" consists of a set of contacts (segmental II mounted on a disk II' similarly to the segments II, and

electrically connected to a ring II which is engaged by the brush I5 connected by lead I! to the lead lb", the ring I4 being fixed to and insulated from the adjacent disk Ila which is driven by the shaft 5; (b) a set of contacts comprising brushes I2' connected by leads I2a' to the direct current main 2; and a set of contacts comprising brushes I2 connected by leads. lid to the direct current main I, the brushes I 2, I2, being mounted and spaced similarly to the brushes I2, I 2, respectively.

The series of contacts for the lead Ic" consists of (a) a set of contacts (segments) II" ;mounted on a disk similarly to the segments II and I II, and electrically connected to the ring II" which is engaged by the brush II" connected by lead It" to the lead lo", the ring II" being fixed to and insulated from the adjacent disk I 4a which is rotated by the shaft 5: (b) a set of contacts comprising brushes I2" connected by leads I2a" to the direct current main 8; and (c) a set of contacts comprising brushes I2" connected by leads Ila" to the direct current min I, the brushes I2", I2", being disposed similarly to the brushes -I2, I2, and I2, I2, respectively.

It will be noted that the disks II, II, II", Ila, are connected to the shaft 5 so that the rings I4, I4, II", and the segments II, II, II". connected thereto, respectively, rotate as a unit.

Referring to Fig. 1, it will be noted (a) that the current in direct current main I is flowing therefrom through leads IIa, brushes I2, segments II, ring I4 and brush II to lead la", the circuit to direct current main I being open since the brushes 12 are engaging the insulation on disk II;\ (b) that the alternating current in lead Ic" is flowing therefrom through brush rin ""ysegments II", brushes I2" and leads I 20" to direct, current main 2, the-circuit from main I beingopen since brushes I2" are engaging the insulation on disk II"; and (c) that the circuit in direct current mains i and I through the brushes I2, I2 is open since the latter are engaging the insulation on the adjacent disk II. In Fig. 2 (a) a portion of the cur-' assaros sulation on the adjacent disk II; and (c) current in alternating current main Ic" is flowing therefrom through brush I5", ring I4", seg- -ments II", brushes I2" and leads I2a" to di- 5 rect current main 2, the circuit to direct current main I being open since brushes II" are engaging the insulation on the adjacent disk II". In Fig. 3, (a) current in direct current main I is flowing therefrom through leads I 2a, brushes I3, segments I0, ring I4, brush II to alternating current main ID", 'the circuit to direct current main 6 being open since brushes I2 are engaging the insulation on the adjacent disk II (b) current in alternating cur- 15 rent main Ic" is flowing therefrom through brush II", ring I4", segments III", brushes l2" and leads I2a" to direct current main 8,'the circuit in direct current main I being open since brushes I2" are engaging the insulation on the adjacent disk II"; and (c) the circuit in direct current mains I, 'I, is open through brushes I2, I2, since the latter are. engaging the insulation on the adjacent disk II. In Fig. 4, (a) a portion of the current in alternatlng current main Ia" is flowing therefrom through brush I5, ring I4, segments I I, brushes I2 and leads I24 to direct current main I, the circuit from direct current main 1 being open since brushes I3 are engaging the insulation on so the adjacent disk II; (b) a portion of the current in alternating current main I c" is flowing therefrom through brush I5", ring ll", segments II", brushes I2" and leads I2a" to direct current main 0, the circuit from direct current main I being open since the brushes I2" are engaging the insulation on the adjacent disk II": and (c) current in direct current main I is flowing therefrom through leads I la, brushes I2, segments Ill, ring I4, and brush I! to alternating current main lb", the circuit to direct current main 6 being open since brushes I2 are engaging the insulation on the adjacent disk II.

In Fig. 5. (a) current in alternating current main I a" is flowing therefrom through brush ll, ring Il, segments II, brushes I2 and leads Ila to direct current main 0, the circuit from direct current main I being open since brushes I2 are engaging the insulation on the adjacent disk II; (b) current indirect current main I is flowing therefrom through leads Ila, brushes I2, segments II, ring I4 and brush I! to alternating current mainlb", the circuit to direct current min I being open since brushes I2 are engagin the insulation on the adjacent disk II; and (c) the circuit in direct current mains 6, I, is open through brushes I2", I2", since the latter are eng ging the insulation on the adjacent disk In Fig. 6, (a) current in alternating current main la" is flowing therefrom through brush Ii, ring II, segments II, brushes I2 and leads III: to direct current main 0, the circuit from-direct current main I being open since brushes it are engaging the insulation on the adjacent disk II; (b) a portion of the current in direct current main I is flowing therefrom through leads I la, brushes I2. segments II, ring II and brush II to alternating current main lb". the circuit in direct current main 2 being open since brushes I2 are engaging the insulation on the adjacent disk II; and (c) a portion of the current in di-'- rect current main I is flowing therefrom through loads Ila", brushes I2", segments II", ring I4" 16 and'brush II" to alternating current main lo".

in are purely illustrative and are the circuit in direct current main 8 being open since brushes I!" are engaging the insulation on the adjacentdisk ll".

It will be understood that the shaft 5 is driven at such speed that it makes one half revolution for each complete cycle of the alternating current impressed on the leads I, 2, 3', and while the views in the accompanying drawing illustrate and the foregoing description refers to the position of the sets of contacts for each alternating current supply lead |a"-l5, |b--l6', lc"l6", throughout one-half .of a complete cycle, it will be understood that as the shaft-5 rotates to make one half revolutionfthe respective pairs of contacts (segments) (brushes) adjacent thereto, respectively, to complete the cycle so that a complete cycle is effected for each half. revolution of the shaft.

re-enga-ge the sets of contacts- What I claim is: 1. In welding apparatus, the combination with a three-phase step-down transformer and alternating current supply mains connected to the a primary windings thereof, of leads connected to the secondary windings of said transformer, rotatable electrodes adapted to engage the work,

. direct current mains connected to said electrodes,

Ill

and current reversing means between each said lead and said direct current mains for connecting said lead alternately to said direct current It will be noted (a) that the segments on each disk are diametrically related and the brushes of each set are diametrically related for simultaneous engagement with the segments and all of the brushes related to each disk I I, II, I l", are uniformly spaced a distance greater than the length of each segment, whereby each pair of segments alternately engage the adjacent sets of brushes and (b) that the segments Iii on the disk H are arranged in a different angular relation about the axis of the shaft 5 as compared to the segments ill on the disk II and that the segments i" on the disk II" are arranged in a different angular relation about the axis of the shaft as compared to the segments Ill on the disk H; I

accordingly, as the shaft 5 rotates, (a) the pairs of segments on the disks II, II, II" are simultaneously moved into engagement with those sets of brushes which are connected to the direct current mains having the same polarity as the cur-l rent in the pairs of segments, respectively, and

(b) due to the spacing of the brushes, eachpair ofsegments in moving out of engagement with one set of brushes into engagement with the other set of brushes, is disengaged from both sets, such disengagement being effected when the phase angle of the current in the lead connected to said pair of segments is zero. It will thus be seen that while there is a reversal of the current in the alternating current mains, the current in the direct current mains is uni-directional at all times. Accordingly, the molecular structure of the welded seam will have a uniform texture and density throughout its length, as contradistin- 'guished from a stitch weld.

It will also be noted that each disk ll, I-i and the adjacent disk Ila may be formed integrally or as a unitary assembly.

It will also be understood that the alternating current mains. I, 2, 5, may be provided with a suitable switch to cut in the current; also a suitable switch may be provided in the leads la, lb, lc, leads la, lb, lo and leads la", lb", lc", leads l6, l5, l5", and direct current mains 6, 1; these switches not being shown as they are of well known construction and one or more thereof may be provided as may be found desirable; likewise a device, such as a rheostat, may be provided to regulate the current to the electrodes 9, 9'.

To those skilled in the art to which my invention relates, many changes in construction and ,widely differing embodiments and applications of the invention will suggest themselves without be in any sense limiting.

mains during the reversal of current therein.

2. A welding apparatus as claimed in claim 1 wherein each said means consists of a set of contacts connected to the adjacent lead and sets of contacts connected to said direct current mains, respectively, and a current reversing device for effecting alternate engagement of said first mentioned set of contacts with said last 'mentioned sets of contacts.

3. In welding apparatus, the combination with a three-phase step-down transformer, a synchronous motor and alternating current supply 'mains connected to said motor and the primary windings of said transformer, of leads connected to the secondary windings of said transformer, a shaft connected to and driven by said motor, sets of segments carried by and insulated from said shaft, each set being connected to one of said leads, rotatable electrodes adapted to engage the work, direct current carrying mains connected to said electrodes, and sets'of contacts for each set of segments arranged to be alternately engaged by the latter, and leads connecting each of the last mentioned sets of contacts with one of said direct current mains, said sets of segments being angularly related about the axis of said shaft to alternately connect each of said sets of segments to the adjacent sets of contacts during the reversal of current in the lead connected to said set of segments.

4. In-Welding apparatus, the combination with a three-phase step-down transformer, alternating current supply mains connected to-the primary windings of said transformer, of leads connected to the secondary windings of said transformer, a, shaft, means for driving said shaft, a conducting ring on the shaft for each of said leads, disks fixed to said shaft, one for each of said leads, diametrically related segments on each of said disks in insulated spaced relation and electrically connected to one of said leads and one of said conducting rings, a pair of rotatable electrodes adapted to engage the work, direct current carrying mains each connected to one of said electrodes, pairs of brushes related to each disk and arranged to be engaged by the segments thereon,the brushes of each pair being connected to one of said direct current mains and diametrically related, whereby the segments alternately engage said pairs of brushes and each brush being uniformly spaced from the brushes of the other pair .of brushes, the adjacent brushes being so spaced relative to the length of the adjacent segments that when the current in the lead connected to said segments is at zero phase angle, the segments are out of engagement with all of said brushes, the segments on the respective disks having different angular relation whereby said segments engage said pairs of brushes in doordinated relation to the reversal of current in said leads.

5. In welding apparatus, the combination with a pair of rotatable electrodes arranged to engage with the stock to be welded and secondarv multL being continuously electrically connected to said alternating current leads, and means for causing alternate engagement of the contacts connected to each said alternating current lead with said adjacent contacts connected to said direct current leads.

6. In welding apparatus, the combination of a 2,839,795. pair 01' rotatable electrodes adapted to engagethe stock to be welded, direct current mains connected to said electrodes. secondary multiplephase alternating current supply mains, and mechanical current rectifying means between said alternating current supply mains and said direct current mains for establishing a continuous direct current circuit through said electrodes and stock.

'I. A welding apparatus as claimed in claim 6 wherein is provided between the alternating current supply mains and said rectifying means a transformer for stepping down the voltage.

' HOWARD I. MORRIS. 

